There exists a finite configuratio- Iran NMO 2005 - Problem4
Source:
September 21, 2010
inductioncombinatorics proposedcombinatorics
Problem Statement
We have a rectangle. We call each square a room and we show the room in the row and column as . There are some coins in some rooms of the rectangle. If there exist more than coin in each room, we can delete coins from it and add coin to its right adjacent room OR we can delete coins from it and add coin to its up adjacent room. Prove that there exists a finite configuration of allowable operations such that we can put a coin in the room .